This invention relates to a method for the prevention and treatment of inflammation.
In the recent past, certain strains of bacteria have attracted considerable attention because they have been found to exhibit valuable properties for man if ingested. In particular, specific strains of the genera Lactobacillus and Bifidobacterium have been found to be able to establish themselves in the intestinal tract and transiently colonise the intestine, to reduce the adherence of pathogenic bacteria to the intestinal epithelium, to have immunomodulatory effects and to assist in the maintenance of well-being. Such bacteria are commonly called probiotics.
Extensive studies have been carried out to identify new probiotic strains. For example, EP 0 199 535, EP 0 768 375, WO 97/00078, EP 0 577 903 and WO 00/53200 disclose specific strains of lactobacilli and bifidobacteria and their beneficial effects.
Inflammation is a complex reaction of the innate immune system that involves the accumulation and activation of leucocytes and plasma protein at sites of infection, toxin exposure or cell injury. Although inflammation serves as a protective function in controlling infections and promoting tissue repair, it can also cause tissue damage and disease. Gastrointestinal diseases such as inflammatory bowel disease (for example Crohn's disease, ulcerative colitis, and pouchitis), food allergies and atopic dermatitis resulting from food allergies are always accompanied by aberrant intestinal inflammatory responses at different levels. The alleviation of this intestinal inflammation by balancing pro- and anti-inflammatory cytokines or induction of regulatory cytokines has been suggested as a possible treatment for these chronic diseases. There are numerous such cytokines of which IFN-γ, IL1, IL8, IL12 and TNF-α for example are regarded as pro-inflammatory and IL10 and TGF-β for example are regarded as anti-inflammatory.
Macrophages are tissue based phagocytic cells derived from monocytes which play an important role in the innate immune response. They are activated by microbial components and, once activated can themselves secrete both pro- and anti-inflammatory cytokines. In “Stimulation of the Secretion of Pro-Inflammatory Cytokines by Bifidobacterium Strains” (Microbiol. Immunol., 46(11), 781-785, 2002) He et al investigated the ability of different bifidobacteria strains to affect the production of macrophage derived cytokines. They discovered that “adult type” bifidobacteria such as Bifidobacterium adolescentis and Bifidobacterium longum induced significantly more pro-inflammatory cytokine secretion than did “infant type” bifidobacteria such as Bifidobacterium bifidum, Bifidobacterium breve and Bifidobacterium infantis. In addition they noted that B. adolescentis in particular did not stimulate production of the anti-inflammatory cytokine IL-I0. They concluded that adult-type bifidobacteria may be more potent to amplify, but less able to down-regulate, the inflammatory response.
More recently, attempts to identify the most promising anti-inflammatory probiotic strains for human use have indicated that the generalizations made by He et al are likely to prove unreliable as it has now been demonstrated that the properties of a specific strain—for example its anti-inflammatory properties—cannot be accurately predicted by reference to its taxonomic classification.